Grenade flotation attachment



M. G. ANGELos Er lAL. GRENADE nounou ATTAGHMENT Filed ne. 1a, 196e @4W j l/ MW ATTORNEYS.

3,482,517 GRENADE FLOTATION ATTACHMENT Mitchell G. Angelus, Cockeysville, and Lewis W. Fleischmann, Randallstown, Md., assignors, by mesne assignments, to the United States of America as represented by the Secretary of the Army Filed Dec. 18, 1968, Ser. No. 784,681 Int. Cl. F42b 27/00 U.S. Cl. 102-64 1 Claim ABSTRACT OF THE DISCLOSURE A smoke grenade flotation attachment consisting of a cup shaped shroud mounted over a canister type smoke grenade and connected thereto by a destructible fuze spacer. Upon ignition the spacer is destroyedand the shroud is extended by combustion of the grenade to provide a otation chamber above grenade.

This invention relates to a flotation attachment for a smoke grenade and more particularly to a cup shaped shroud slidably mounted over a smoke grenade canister which when extended provides positive buoyancy for the entire grenade assembly.

Smoke grenades of the type that are dropped from low flying air craft into water are sometimes provided with a pressure retention chamber at their upper ends to control the burning of the smoke mix. This chamber is lixed to the smoke mix canister and is lvulnerable to damage in handling and dropping. Since the chamber was limited to a rather small size it did not alord positive buoyancy to the grenade assembly.

The present invention is designed to overcome the aforesaid disadvantages by a -cup shaped shroud connected at its top to the canister by .a destructible fuze spacer. The shroud cannot be extended until the fuze spacer is destroyed by the heat of the burning smoke mix, thus affording extra protection to the assembly while closed, but providing a chamber of suflicient length when extended, so that the volume of water it displaces will result in positive buoyancy for the entire grenade assembly.

A grenade having a fixed pressure retention chamber iS seen in U.S. Patent No. 3,372,641.

It is therefore a principal object of this invention to provide positive buoyancy of a smoke marker grenade when dropped into water.

Another object is to provide a cup shaped shroud slidable on a smoke marker canister which, when fully extended will displace a volume of water suflicient for positive buoyancy of the grenade assembly when in water.

A further object is to provide a telescopic shroud on a smoke marker canister and connected thereto by a destructible fuze spacer when in collapsed state.

A still further object is to provide means to prevent separation of the cup shaped shroud from the canister when fully extended.

Another object is to provide means to prevent collapse of the cup shaped shroud when fully extended.

These and other objects and advantages of the present invention will be fully apparent from the following description when taken in connection with the annexed drawing, in which:

FIG. 1 is an axial section taken through a smoke marker grenade constructed in accordance with this invention, the shroud being shown as collapsed;

FIG. 2 is an enlarged detail view showing the manner in which the shroud is prevented from separating from the canister when fully extended;

`United States Patent O Patented Dec. 9, 1969 ice FIG. 3 is a view similar to FIG. 1 but showing a modified form having means for preventing separation and collapse of the shroud relative to the canister, and,

FIG. 4 is an enlarged detail view similar to FIG. 2 showing the means for preventing separation and/or collapse of the shroud.

VReferring to the drawing in which like reference characters designate like parts throughout the several views, reference character 1 indicates generally the smoke grenade assembly of this invention. Assembly 1 includes a canister type smoke grenade 2 which is provided with a cover 3 crimped to the wall of canister 2 at its upper end as at 4. The bottom is similarly constructed and includes a crimp S as shown. Canister 2 contains a smoke mix 6.

A cup shaped shroud 7 is slidably mounted on canister 2 as shown and this shroud is of a length longer than canister 2 and is connected thereto by a destructible spacer 8 which is located axially and attached at its upper end to shroud 7. An internally threaded socket 9 is carried axially by cover 3. Spacer 8 is internally threaded for a distance as at 10 and is further provided with an externally threaded portion 11 which is threadably attached to socket 9. A fuze assembly 12 having an externally threaded portion 13 is threadably mounted in threads 10. Fuze assembly 12 also includes the conventional retention handle 14 and safety pin 15. Exhaust ports 16 are provided at the top wall of shroud 7 and may be covered by tape 17. While only one port 15 is shown, they may Vary in number as is expedient.

Means are provided to prevent separation of shroud 7 from canister 2 when extended and consists of a split locking ring 18 which is fitted into an annular crimp 19 located at the bottom rim of shroud 7.

Spacer 8, which is for the purpose of containing the fuze assembly and to connect the shroud 7 to the smoke canister 2, is made of a material which fails structurally when a specic load is placed thereon and/or a specic temperature is reached. An example of such a material is Cerrobend which is an alloy of bismuth, lead, tin and cadmium and has a melting point of 158 F.

The operation of assembly 1 is as follows: after handle 14 is released by removal of safety pin 15, assembly 1 is dropped into the water. The fuze assembly 12 operates to fire the smoke mix 6 in canister 2. The combustion gas pressure therefrom blows ol cover 3 and builds up in retention chamber 20 to blow off tape 17 and permit smoke to escape from ports 16. The heat from the combustion destroys spacer 8 and this permits the pressure to telescope shroud 7 upwardly. When full movement of shroud 7 is reached, further extension of the shroud 7 is prevented by contact of snap ring 18 ywith crimp 4 which stops its upward movement as shown in FIG. 2. As long as the burning exists, combustion gas pressure prevents collapse of shroud 7, and since the center of gravity will be located at the lower end of the assembly and it will oat upright, thus permitting smoke to exit through ports 16.

Upon exhaustion of smoke mix 6 in canister 2 the center of gravity is disturbed and the assembly will fall over on its side and eventually water entering ports 16 causes it to sink.

In FIG. 3 there is illustrated a modified form of otation attachment for a smoke grenade. Grenades which have been stored for a long time have exhibited reduction in burning rates Which could Cause collapse of the shroud 7 when coming into contact with cold water.

The embodiment shown in FIG. 2 eliminates this danger by providing a spring clip 21 lixed to the inner wall of shroud 7 and disposed near the bottom thereof as shown.

In this form, a split ring is not used, but rather a snap ring 22 having an annular groove 23 which receives a crimp 24 of the rim of shroud 7 therein.

The spacer 8a of this form is shown as locked in the socket 9. A reduced portion 25 having a head 26 snaps into the socket 9 instead of being threaded into it.

The operation is the same as in FIG. l with the exception (see FIG. 4) that when snap ring 22 is stopped by crimp 4, spring clip 21 will have been pushed in by crimp 4 to snap back and contact the top of canister 2 and prevent return of the shroud 7 from its extended position. In this form tape 27 could be used to protect the assembly against moisture.

What is claimed is:

1. In combination with a smoke marker grenade ncluding a canister containing a smoke mix, said canister having an annular crimp at its upper and lower ends and having a cover therefor, a destructible spacer carried centrally by said cover and a fuze assembly detachabl;r secured in said spacer; a flotation attachment for said grenade comprising an inverted, cup shaped shroud secured at its end between said spacer and said fuze assembly whereby a pressure retention chamber is formed at the top of said canister, said shroud receiving said canister and extending downward to a point near its bottom and having an annular crimp adjacent its bottom end, a snap ring having an annular groove in its outer periphery and receiving said annular crimp in said shroud therein, its inner periphery slidably contacting said canister, and a leaf spring clip secured at one of its ends to the inner Wall of said shroud, its other end being free and biasing against said canister and being spaced above said annular crimp at a distance whereby said shroud is eX- tended to its full position said clip will ride over said upper crimp on said canister and spring out to be engaged against its top and said snap ring will belinrcontact with said upper crimp on said 'canister to lock said shroud in said extended position and to maintain saidsnap ring snugly thereagainst to provide a seal between said canister and said shroud.

References Cited UNITED STATES PATENTS 2,114,213 4/1938 Clauser 102-7 .2,334,211 11/1943 Miller 102-7 X 2,814,249 11/ 1957 Brennan et al. 102--7 3,372,641 3/ 1968 Foster 102-65 3,427,973 2/ 1969 Beers 102-65 BENJAMIN A. BORCHELT, Primary Examiner JAMES FOX, Assistant Examiner Us. c1. X.R. y 

